Now, to growing fears about a potentially deadly virus spreading in the U.S. One hospital worker in Florida who may have been exposed to mers has been admitted. And there are fears hundreds more may have come in contact with the patient. ABC's Steve osunsami is in Atlanta at the centers for disease control. The CDC. Morning, Steve. Reporter: Good morning, robin. We've been talking to investigators at the CDC tracking this. And they underline this has spread through extended contact. Their big concern is over anyone who flew on a flight with this patient. Health officials here and in the U.K., now, are trying to track down every, single passenger on this patient's domestic and now international flights. This morning, doctors worry that the second sick traveler to arrive in the U.S. From the middle east may have infected two health care workers who treated the 44-year-old patient at Orlando hospitals last week. They're already showing symptoms of mers. The member was admitted because he did meet a criteria for admission. Reporter: Mers or middle eastern respiratory syndrome is a new imported disease. It's not as contagious as the cold or flu. But it kills nearly one-third of its victims. To be safe, doctors sent home 20 health care workers who had contact with the patient. Told to look out for symptoms for the next two weeks. They're warning at least 80 people who may have been exposed in hospital waiting rooms. Health officials trying to ease fears. The risk is negligible to this community. I think the risk is negligible to those in the waiting room. Reporter: The patient who works as a health care provider in Saudi Arabia, entered the U.S. In Boston. Then, flew to Atlanta, before landing in Orlando. The CDC is working with authorities from 20 states to find every passenger on the Florida patient's American flights. Posting warnings at the airports. They believe that mers is spread through close contact over long periods of time. And it might be coughs that spread the virus the most. This is a new virus. There's no specific antiviral medicine. And there's no vaccine. Reporter: It takes 2 to 14 days to come down with this. And for now, there is no cure. Robin? We heard. No vaccine, Steve. Now, to Amy who has the

This transcript has been automatically generated and may not be 100% accurate.

Health Alert for Every Airport in America

Two confirmed cases of deadly MERS virus now in America.

Deadly MERS Virus Appears in US

The government has identified the second case of the virus in 10 days.

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